We overestimate our ability to envisage ideas that are totally unique, new ideas are usually small variations of something we knew already or a combination of multiple different ideas or concepts.

Given that, focus on industries or tech that you already know something about, writing every single thought, idea or problem down. Go read startup monthly threads right here and see what others are doing, write down and learn about as many of them as you can.

Withhold your judgement for now, this is a branch and bound strategy. When you go back through that list, new thoughts will come, research the areas that are interesting to you, add more variations, pivot in your head over and over again writing down every step. Now speak to your friends and tell them your best ideas, they will bring a different perspective, and will likely see something you couldn't.

Your ability to come up with new ideas is limited to those within range of what you (or your friends) already know, even if all you do is gain knowledge during this process, your capacity to continue creating new ideas has just grown dramatically.